课后练习：

1. Thisis roughly the _____ of 4195 cigarettes a year for every person in the countryof 18 years of age or more.

A. equal B. equality C. equivalent D. equator

2.Research teams have conducted studies that show beyond all reasonable doubtthat tobacco smoking, particularly cigarette smoking, is associated _____shortened life expectancy.

A. to B. with C. by D. in

3._____ smoking, if you don’t smoke----don’t start.

A. Give in B. Give away C. Give up D. Give off

4. Some____ physicians and research workers are less sure of the effect of cigarettesmoking on health.

A.compete B. competent C. competitive D. competence

5.Smokers who develop cancer or lung diseases may also, _____, live in industrialareas or eat more canned food.

A. by coincidence B. in coincidence

C. withcoincidence D. of coincidence

6. Itis estimated that 51% of American men smoke _____ 34% of American women.

A. comparing with B. comparing to

C. compared with D. compare to

7. Onepoint of concentration is ______ the air tube, or bronchus, divides.

A. which B. where C. what D. how

8.Current research indicates a _____ relationship between all forms of smoking ancancer of the mouth and throat.

A casual B causal C cause D course

答案：1 C 2 B 3 C 4B 5 A 6 C 7B 8 B

补充练习：

1. Female smokersarethought tobe less becausethey do not breathe in the smoke so deeply.

A. effect B. affect C.effected D.affected

2. Gradually, however, researchis isolating all other possible factors and proving them to be statistically .

A. relevant B. irrelevant C. relate D.relative

3. the scientificstatistics, it might be helpful to look at what smoking tobacco actually the human body.

A. Apart from/ does to B. Part from/ do to

C. Apart for / does to D.Apart to/ does to

4. Whileall tobacco smoking affects life and expectancy and health, cigarette smokingappears to than cigar orpipe smoking.

A. have a much greater effect B. have a muchgreat effect

C. have a much great effects D. has a much greater effect